This is an age-old problem men have always had. What to do when she won't break away from her pack of friends.
If she has made eye contact with you and smiled. You must move in immediately. Don't wait for her to break from the pack. I know you want to refrain from any embarrassment from her friends. Remember, women look for confidence in a man. If you wait, you will lower her interest in you and risk the chance of someone else moving in on your target and you will look like wimp in her eyes.
So how do you introduce yourself without looking like a complete idiot?
If she's in a group with more then one women. Bring a friend with you. The friend can be a lifesaver and will take a lot of pressure off the initial contact. You might want to want to train your friend in advance.
Another approach is very low risk. If your at a pub, have a waiter deliver a note with a quick message saying something like " Hey, I know you're with friends, but if you'd like to make another friend, step away for a second. (Don't make me come over and start singing to you.)"
More then likely she will come over unless she is totally not interested or is extremely shy. When she gets to your table. "You might want to say something like "I don't normally interrupt people during lunch, but I just had to give you the pleasure of meeting me." (Give her a playful smile.) "What's your name?"
It’s always best to tease a bit and also to be a little cocky. It shows the women your strong and confident. Women tend to be a little turned off by the "nice guy" who can't get the courage to go after what he wants.
Typically, women want a dominant man in a relationship. And when I say dominant. What I mean is a guy who takes control of the relationship and is a source of strength for the woman he's with. A man who makes her feel safe and eliminates uncertainty from her life.
So when you see a girl in public that catches your eye. And she seems to be interested in you. Go up to her. Introduce yourself and Bam! You have a chance of meeting the girl of your dreams.
Source: http://www.a1articles.com/article_215378_39.html
